Rough or no idle

Tiny
GARA MOORE MORTON
  • MEMBER
  • 1992 GMC TYPHOON
  • 141,000 MILES
Engine has been running good, no problems. Went for a drive and engine started running rough at 2000 rpm, anything above 2000 rpm runs fine. Now it will not idle. Tachometer jumps around below 2000 rpm. Any help would be greatly appreciated. Skip Morton, retired tune up shop owner, Thanks.
Thursday, February 23rd, 2017 AT 1:31 PM

5 Replies

Tiny
STEVE W.
  • MECHANIC
  • 15,111 POSTS
Which color combo do you have? It is the one version of the S-Series I always wanted but never could find one "reasonable" at the time.

CEL on? Fuel mileage change?

Anyway, rough idle on the 4.3 was usually the EGR sticking open from a chunk of carbon or failing diaphragm. I would think the turbo would only make that worse. The other was the IAC sticking or getting clogged.
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Thursday, February 23rd, 2017 AT 2:49 PM
Tiny
GARA MOORE MORTON
  • MEMBER
  • 3 POSTS
White with gray cladding, No check engine light or codes. I can only hope it is not the IAC that valve is really hidden. Thanks, I will let you know.
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Thursday, February 23rd, 2017 AT 4:16 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 53,853 POSTS
Please let us know happens.

Best, Ken
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Sunday, February 26th, 2017 AT 12:09 PM
Tiny
GARA MOORE MORTON
  • MEMBER
  • 3 POSTS
02 sensor covered with carbon, cleaned it, back to running good. Replaced IAC and temp. Sender with no change. THANKS.
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Sunday, February 26th, 2017 AT 10:05 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 53,853 POSTS
Nice work, we are here to help, please use 2CarPros anytime.

Best, Ken
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Monday, February 27th, 2017 AT 10:31 AM

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